The invention relates to a torso and forearm supporting device, such as in one embodiment, a swivel chair mounted on a roller base for use in a chest-supported straddle posture, having the capability of being used in a back-supported posture as well, with cushioned chest support and articulated forearm supports that follow the user""s arm movement while providing continuous forearm support.
In order to suit the body positions required during work by industrial or commercial workers, surgeons or dentists, various ergonomic, multi-position work stands and chairs have been developed.
In industrial or commercial applications, workers are often required to remain seated or standing in one position for extended periods of time. For example, during welding operations, in an assembly environment, in a food processing operation, during clerical work such as typing or mail sorting, or during surgical or dental operations, the arrangement and configuration of seating or standing positions varies considerably. Flexibility and ease of positioning equipment is highly desirable to suit the individual needs of a person, their particular preferences in position or a variety of positions and to suit the industrial or commercial operations in which they are engaged.
In the past, clerical or industrial workers were expected to stand or sit in fixed and/or suspended positions with very little consideration of their comfort or physical well-being. In recent years, however, ergonomic seating, accident prevention and prevention of fatigue have become very prominent concerns for workers and employers alike. Many medical conditions are caused by extended physical strain usually resulting from a fixated or suspended body position or repetitious movement during work activities. For example, in keyboard-related work, the carpal tunnel syndrome has become a well-known condition caused by the compression of the nerves that pass through the wrist into the hand and is characterised by weakness, pain and disturbances in the nerves of the hand. Many proposed solutions to this syndrome have been made in the prior art geared generally to resting the forearm or wrists of a typist on a stationary wrist or forearm support in a particular position.
Examples of clerical-type supports are found in U.S. Pat. No. 4,650,249 to Serber that shows an ergonomic seating assembly including knee support pads and a wrist support platform. U.S. Pat. No. 4,832,405 to Serber also shows a variable posture chair wherein the user may take a back-supported seating position in a traditional manner and may also support their chest by taking a chest-supported straddle position sitting with elbows or forearms resting on lateral armrest extensions of the seat back.
Some of the prior art systems are very complex, with multiple components that require cumbersome adjustments. In such cases, the advantages of wrist and chest support do not overcome the disadvantages caused by interference to normal body movement due to the mechanical complexity of the device. One example is shown in U.S. Pat. No. 5,542,746 to Bujaryn which includes knee supports, chest supports, adjustable arm and wrist supports that many users would find baffling and that would unduly interfere with normal activities.
It has been recognized in the prior art that surgeons, dentists and industrial workers can also benefit from improved physical support during their work since they must remain in a fixed position, leaning over a patient for example, for extended periods of time. For example, U.S. Pat. No. 3,754,787 to Garber provides a saddle-type seat with a chest support to enable surgeons in an operating room environment to remain in a standing or sitting position leaning over a patient for extended periods of time. The surgeon""s hands and arms are completely suspended while they lean over the patient, with their chest supported on a cushioned pad. Standing for extended periods of time without chest support in this type of position becomes extremely uncomfortable and stressful.
A further example of non-clerical body supports is shown in U.S. Pat. No. 5,295,728 to Schaevitz which shows a multi-position work stand with a bicycle type adjustable seat and back rest that can be used in various positions to support workers during industrial activities.
A significant disadvantage of many of the prior art devices is that while they are suitable for certain specialised uses, they are not generally suitable for both general office seating and specialised positions. An example of this disadvantage can be seen in a dental office environment. Quite often the practitioner uses the same conventional swivel chair to perform office type work at a desk as well as to carry out typical dental examinations. In such situations a conventional office swivel chair may be all that is required. However, the dentist is also often required to stand and lean over a patient for extended periods of time. A specialised work stand is simply impractical since the dentist""s working environment is typically congested, and space for additional equipment is very limited.
The same disadvantages can be found in many industrial applications such as soldering, welding, assembly of electronic or mechanical components, or in chemical laboratories where workers are often seated at a desk, counter or workstation table on a conventional swivel-type chair. Workers are often required to maintain their arms in positions that result in fatigue and undue stress over extended periods of time. For example, during electrical assembly, soldering or welding, workers may be required to lean their elbows on the work piece or on a worktable to maintain their forearms in a fixed position. The costs and space requirements necessary to install specialised arm supports or work stands to support the workers in a chosen position are simply too impractical and not cost-justified. Even if specialised work stands were provided, many workers would simply reject them if they were overly complex and required adjustments that interfered with normal work patterns.
A distinct disadvantage of many prior art armrest supports is that the armrests remain stationary. As a result, the user must slide their forearms repeatedly over the arm rests and potentially suffer friction burns or abrasion. For example, U.S. Pat. No. 4,277,102 to Aaras et al. provides armrests that can be adjusted to any fixed position or orientation. However, sliding on the fixed supports will eventually result in abrasion or discomfort, if the user must move their arms often during work operations.
Recognizing this problem, U.S. Pat. No. 5,281,001 to Bergsten et al. provides a sliding and rotating arm support that enables the user to retain their forearm or elbow in the arm rest support and track the motion with a smooth linear ball slide arrangement. The Bergsten device does not include rotational adjustment and therefore can operate in a generally horizontal plane only. In addition, the Bergsten device includes a horizontally sliding arm disposed on an armrest at kidney or underarm height that likely interferes with the use of the chair or work area by unexpectedly prodding, slapping or poking the inattentive user.
Therefore, it is an object of the invention to provide an arm support that dynamically follows and simulates natural arm movement with minimal disruption to the natural arm motion of the user and with minimal cumbersome manoeuvring of an apparatus.
A further object of the invention is to provide a simple effective means to fully support any individual who is required to sit or stand in a fixated position with suspended forearms for prolonged periods. It is a further object of the invention to provide a torso and forearm supporting chair with chest support that is equipped with forearm supports and can alternatively be used in a conventional back-supported seating position with arm supports used in a conventional lateral position or alternatively retracted so that they do not interfere with normal working actions.
It is a further object of the invention to provide arm supports that actively follow the motion of the user""s arms and do not require the user to slide their forearms over potentially abrasive fixed supports during working motions.
Further objects of the invention will be apparent from review of the disclosure, drawings and description of the invention below.
A torso and forearm supporting device for supporting the body of a user resting in a seated or standing position is provided. The device includes a support base, such as a swivel chair base or foot-rest floor mounted platform. A post assembly is mounted extending upwardly from the base and a torso support pad is disposed on the top end of the post assembly to support the user in a chest-supported position by engaging the user""s chest. Alternatively, the torso pad can be used to support the user in a back-supported position by engaging the user""s back. Forearm supports allow the user to rest at least one forearm during forearm movement while continuously engaging the armrest.
A seat can be mounted to the base, for seating the user in the chest-supported position straddling the post assembly and also in the back-supported position. Alternatively, the support base can include a foot-rest floor mounted platform and an upright stanchion extending from the floor mounted platform, with a top portion of the stanchion including a post assembly mounting connection.
A preferred configuration includes articulated armrest brackets that fold in a compact manner behind the post assembly for storage when not in use.
A chair configured embodiment of the invention therefore provides for a chest-supported straddle posture chair or front-leaning standing (upright) posture where the pad mounted to the post assembly can be used to engage the chest of the user.
Moreover, the chair is also adapted for conventional office or industrial environments to seat the user at a desk or workstation in a back-supported seating position using the same pad mounted to the post assembly to support the user""s back. The forearm supports conveniently fold in a compact unit behind the back of the user. Unlike some of the armrests of the prior art, these forearm supports will not interfere with the usual activities of the user, when not required.
The pedestal on which the seat cushion of the chair rests is fixably or slidably adjustable such that the user can adjust the seat forward or rearwardly along the median line for optimal positioning of the user""s centre of gravity relative to the base in either of the seating orientations. The capacity to adjust the seat position prevents the chair from overturning when the user changes position from the chest-supported straddle posture to the traditional back-supported posture using the same seat, pedestal and support base.
Another embodiment of the invention provides torso and forearm support to the user in a standing position. The post assembly can be mounted to an upwardly extending stanchion supported on a floor mounted base. The same post assembly with forearm rests and chest/back pad can be mounted for standing or seated positions on different bases.
An advantage of the invention is the unique combination of a torso support together with individually adjustable forearm supports that continuously engage the forearm of the user and follow the motion of the user""s arm within a predetermined transverse plane. A preferred embodiment in the invention, for example, includes an articulated linkage that supports the forearm of the user within a plane that is transverse to the post assembly. Individual adjustments of the two arm rests are permitted with sliding adjustment on the post assembly and rotational adjustments to suit the particular position of each arm required by the operation carried out by the user.
A distinct advantage of the invention is the ability of the linkage members to fold together in overlapping relation into a compact unit that is retained behind the post assembly when not in use. In contrast, many of the prior art armrests are quite inconvenient and interfere with normal use of the chair when a specific support in a specific position is not required.
Further advantages of the invention will be apparent from the following detailed description and accompanying drawings.